1.\" $OpenBSD: shutdown.8,v 1.44 2023/06/19 13:05:25 deraadt Exp $ 2.\" $NetBSD: shutdown.8,v 1.6 1995/03/18 15:01:07 cgd Exp $ 3.\" 4.\" Copyright (c) 1988, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)shutdown.8 8.1 (Berkeley) 6/5/93 32.\" 33.Dd $Mdocdate: June 19 2023 $ 34.Dt SHUTDOWN 8 35.Os 36.Sh NAME 37.Nm shutdown 38.Nd close down the system at a given time 39.Sh SYNOPSIS 40.Nm shutdown 41.Op Fl 42.Op Fl dfhknpr 43.Ar time 44.Op Ar warning-message ... 45.Sh DESCRIPTION 46.Nm 47provides an automated shutdown procedure for superusers 48to nicely notify users when the system is shutting down, 49saving them from system administrators, hackers, and gurus, who 50would otherwise not bother with such niceties. 51When the 52.Nm 53command is issued without options, the system is placed in single 54user mode at the indicated time after shutting down all system 55services. 56.Pp 57Users in the 58.Va _shutdown 59group can also run the 60.Nm 61command. 62Historically this permission was tied to the 63.Va operator 64group. 65.Pp 66The options are as follows: 67.Bl -tag -width Ds 68.It Fl d 69When used with 70.Fl h , 71.Fl p , 72or 73.Fl r 74causes system to perform a dump. 75This option is useful for debugging system dump procedures or capturing the 76state of a corrupted or misbehaving system. 77See 78.Xr savecore 8 79for information on how to recover this dump. 80.It Fl f 81Create the file 82.Pa /fastboot 83so that the file systems will 84.Em not 85be checked by 86.Xr fsck 8 87during the next boot. 88(See 89.Xr rc 8 ) . 90.It Fl h 91The system is halted at the specified 92.Ar time 93when 94.Nm 95execs 96.Xr halt 8 . 97.It Fl k 98Kick everybody off. 99The 100.Fl k 101option 102does not actually halt the system, but leaves the 103system multi-user with logins disabled (for all but superuser). 104.It Fl n 105When used with 106.Fl h , 107.Fl p , 108or 109.Fl r 110prevents the normal 111.Xr sync 2 112before stopping the system. 113.It Fl p 114The system is powered down at the specified 115.Ar time . 116The 117.Fl p 118flag is passed on to 119.Xr halt 8 , 120causing machines which support automatic power down to do so after halting. 121.It Fl r 122.Nm 123execs 124.Xr reboot 8 125at the specified 126.Ar time . 127.It Ar time 128.Ar time 129is the time at which 130.Nm 131will bring the system down and 132may be the word 133.Ar now 134(indicating an immediate shutdown) or 135specify a future time in one of two formats: 136.Ar +number , 137or 138.Ar yymmddhhmm , 139where the year, month, and day may be defaulted 140to the current system values. 141The first form brings the system down in 142.Ar number 143minutes and the second at the absolute time specified. 144.It Ar warning-message 145Any other arguments comprise the warning message that is broadcast 146to users currently logged into the system. 147.It Fl 148If 149.Sq Fl 150is supplied as an option, the warning message is read from the standard 151input. 152.El 153.Pp 154At intervals, becoming more frequent as apocalypse approaches 155and starting at ten hours before shutdown, warning messages are displayed 156on the terminals of all users logged in. 157Five minutes before 158shutdown, or immediately if shutdown is in less than 5 minutes, 159logins are disabled by creating 160.Pa /etc/nologin 161and copying the 162warning message there. 163If this file exists when a user attempts to log in, 164.Xr login 1 165prints its contents and exits. 166The file is removed just before 167.Nm 168exits. 169.Pp 170At shutdown time a message is written in the system log, containing the 171time of shutdown, who initiated the shutdown and the reason. 172A terminate 173signal is then sent to 174.Em init 175to bring the system down to single-user state (depending on above 176options). 177The time of the shutdown and the warning message 178are placed in 179.Pa /etc/nologin 180and should be used to 181inform the users about when the system will be back up 182and why it is going down (or anything else). 183.Pp 184You can cancel a scheduled shutdown with the 185.Xr kill 1 186command by killing the shutdown process. 187.Sh FILES 188.Bl -tag -width /etc/rc.shutdown -compact 189.It Pa /etc/nologin 190tells login not to let anyone log in 191.It Pa /etc/rc.shutdown 192run by 193.Xr rc 8 194before the system is shutdown 195.It Pa /fastboot 196tells 197.Xr rc 8 198not to run 199.Xr fsck 8 200during the next boot 201.El 202.Sh SEE ALSO 203.Xr kill 1 , 204.Xr login 1 , 205.Xr wall 1 , 206.Xr halt 8 , 207.Xr rc.shutdown 8 , 208.Xr reboot 8 209.Sh STANDARDS 210The hours and minutes in the second time format may be separated by 211a colon 212.Pq Sq \&: 213for backward compatibility. 214.Sh HISTORY 215A 216.Nm 217command first appeared outside of Bell Labs in PWB/UNIX 1.0 218and has been available since 219.Bx 4.1 . 220